Fractional distillation



R. B. CHILLAS, JR

Feb. 18, 1930.

Original Filed June 30 F .4

FRACTIONAL DI STILLATI ON 2 z @INWE&0R )IL BY MQQ 1 x ATTORNEY seamed Feb. 18, 1

UNITED STATES RICHARD B. CHILLAS, 33., OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR, BY MESNE PATENT OFFJCE' A8BIGNMENTS, T O THE BARRETT COMPANY, 01' NEW YORK, N. Y., A CORPORATION or mnw JERSEY Original No. 1,812,572, dated December 28, 1926, Serial No. 40,536, filed June 30, 1925.

- reissue filed December 27,

I My invention relates to apparatus for fractionally distilling composite liquids, in general, and particularly mineral oils, such as coal tar distillates or the like, and more par- 10 type, in which the rising vapors and refluxing liquid are so controlled that the quality of the products: remains substantially constant notwithstanding ditions. n

In accordance with my invention, products of substantially constant quality are obtained by maintaining substantially constant the ratio of the quantities of the rising vapors t0 the quantities of refluxing liquid.

More particularly in accordance with my invention, the total or entire stream of descendingvor reflu'xin li uid is divided into streams consisting 0 de nite percentages of the total descending liquid, one of the streams being removed as a desired product and another serving as refluxing liquid descending further in the column; and the rate of flow of variations in operating coneach of these streams bears to the rate of flow of the vapors entering the fractionating sys- 30 term a constant or fixed ratio, notwithstanding variations in the quantities of said vapors entering the system per unit of time. I

Further in accordance with my invention, theseratios may be arbitrarily variedby suitable mechanical adjustments and fixed at any desired values'so as to produce streams of the desired qualities, these values then remaining constant notwithstanding fluctuations in" the rate of vapor input.

My invention resides in apparatus of the character hereinafter described and claimed.

Fractional distillation as commonly practiced, in batch operation, comprises distillation of a quantity of the composite 1i uid, and the passage of its vapors through a. ractionating column, such as, for example, ot-the bubble type. The vapors leaving the column are condensed, and a portion of the condensate returned to the top of the column,

FRACTION AL DISTILLATION Application for 1928. Serial No. 328,673.-

liquid. The vapors rising in the column come into intimate contact with the descending or refluxing liquid, with resultant interchange of constituents, those of lower boiling point in the descending liquid pass into the vapor phase in exchange for which those of higher boiling point in the rising vapor pass 1nto the liquid phase, and the eventual liquid reflux returns from the bottom of the column into the still. In such a system, other, variables bein eliminated, the degree of fractionation epends upon the ratio of the quantity of refluxing liquid to the quantity of rismg vapors.

Where the fractionating column is utilized na process of continuous distillation, that 1s, when the composition of the vapor entering the column is approximately constant, it is usually the practice to take off the desired fractions from the top of the column and to draw ofi the reflux from the bottom of the column as a second and higher boiling fraction. Advantage is frequently taken of the change in the composition of the reflux as it descends in the column, and one or more additional fractions are drawn off from the reflux at one or more points between the top and bottom of the column. This is generally accomplished by taking off at one or more of said intermediate points the desired amounts of desired fractions at substantially constant rates, as determined, for example, by set valves. Such system is disadvantageous in that notwithstanding fluctuations, which are almost certain to occur, in-the rate of delivery into the column of the material to be fractionated, the rate of withdrawal of desired fractions remains substantially constant, with resultant variation from substanr tial constancy of the ratio of quantities of yapor, to quantitles of reflux 1n the several column sections or stages, and in consequence,

the operating conditions in the column are changed, with resultant changes in the com- .50 in which'it flows downwardlyas refluxing.v descending or refluxing liquid, the volume as below.

of the desired fraction varying directly with.

the volume of the total descending liquid, and accordingly, the reflux through the column is always substantially in the proportion 5 required to effect products of uniform or substantially constant quality underv varying operating conditions, such as changes in the rate of input of the material to be fractionated. An increase or decrease in the quantity of vapors to 'be fractionated in the column causes corresponding or proportional change in the quantity of refluxing liquid throughout the column.

For an understanding of my invention and for an illustration of one of the various forms of apparatus utilizable in accordance with my invention, reference may be had to the accompanying drawing, in which:

Fig. 1 is a vertical sectional view of a fractionating column and flow box, with associated apparatus;

Fig. 2 is a vertical sectional view, on enla ged scale,-taken on the line 22,Fig. 1;

r Fig. 3 is a horizontal sectional view taken on the line 3-3, F i 2.

caps b, disposed above and spaced from the upwardly directed ports 0. Each plate B is provided also with a tube or pipe d extend-- ing therethrough to a short distance above it and to a point suitably adjacent the plate It will be understood; however, that my invention is not limited as regards the type of fractionatin column or tower utilized, and it' will be un erstood that any other or equiv- 40 alent type may be utilized, including'a packed fractionating column or tower.

The material tobe fractionated is delivhered, atsuitably elevated temperature, into the column A throughthe pipe C, preferably I at a point above one or more of the lowermost plates B. When steam is utilized in the column it may be introduced through the pipe vD into or adjacent the bottom of the column.

E is a vapor line or pipe connecting the top of the -column with the condenser F, from which the condensate of the lowest boiling desired fraction is delivered into a flow box H, of the character hereinafter described, or which may be any other equivalent means for dividing the condensate into a stream for- P wardly flowing through the pipe K to storage or'elsewhere andbearing a definite ratio, va-

- riable at will to the magnitude of the reflux stream returnin through the trapped pipe J into the top of t e column A. j

Operatively related to the column A at'suitable or desired number of points vertically thereof between its top and bottom arethe flow boxes M, M M, etc. While flow boxes are indicated and more particularly described h pi herein, it will be understood that any equivalent means may be utilized for effecting a diing R, in which is disposed a vertical partition or dividing wall S; Upon the vertical pivot shaft V, operable from the exterior by its head X, carrying the pointer or indicator W, is secured-the trough or pan T, open at its front end t and' swingable across the member. S, which to the right of the trough T, Fig. 2, extends to a suitably higher level. The .partition S divides the casingR into two compartments R and R, with which connect,.rev V spectively, the trapped pipes P and N. A

L delivers into the trough T the total liqui' descending in the column A, and this stream is divided by the artition S into streams bearin predetermined relation to each. other an entering, respectively, the compartments R and R from the former of which the pipe P conducts the reflux liquid back into the column A at suitable. height therein; and the liquid delivered into the compartment IR is delivered through the pipe N to storage or other suitable destination after cooling, if desired, in a cooler 0.

Each of the other flow boxes M, M, etc., is connected in the system b associated pipes L, L, etc., P P etc., an N N etc., coolers O 0 etc., being utilized if suitable or desirable.

By manipulation of the head X of the flow box H the proportion of the reflux liquid returned to the column through the pipe J to the forward stream of desired condensate is determinable. And similarly, in each of the flow boxes M M etc., by similar adjustment of its trough T with "respect to it's partition S,

the amount offorward flowing fraction or distillate is proportioned with respect to amount returned as reflux into the column A.

When the material to be fractionated and. introduced through the pipe 0 is to a considerable extent or wholly l1 uid, heat may be applied to the material in t e column by any suitable means, as by steam introduced through the pipe D. When steam is utilized, the water may be separated from the condensed oil vapors between the condenser F and the flow box H, whereby only liquid oil is delivered to the flowsbox H.

The vapors pass upwardl through the column'and thence through the pipe E to the condenser F as aforesaid, a portion of the condensate returning to thencolumn through the pipe J as reflux. The refluxing liquid one or more points between the top and bottom of the column the entire quantity of the refluxing liquid is drawn off to a flow box, or e uivalent, to effect division into streams w ose magnitudes bear a fixed relation to each other, one of them constituting a desired sirable.

The column A and the flow boxes may be lagged or covered with suitable heat-insulating material.

The several flow boxes are in effect in series or tandem with each other, in the sense that the descending refluxing liquid passes through them in succession, the total refluxing or descending liquid for each stage or section of the column passing through the associated flow box. In effect, therefore, the refluxing or descending liquid throughout the column is subjected at suitable intervals and successively to division into streams bearinga substantially constant ratio to each other.

By a system of the character described, notwithstanding variations in the amount of material to be fractionated delivered into the column Athrough the pipe 0 per unit of time, the several fractions, and especially those as taken ofif through the intermediate flow boxes M, M, M", etc., remain of substantially fixed ualit which characteristic results from the act t at the quantities of the rising vapors bear a substantially constant -ratio to the o quantities of the descending refluxing liquid in'each section or stage of the column, and from the-fact that for each section .or stage of the column the entire stream ofdescending refluxing'liquid is divided into streams, as aforesaid, bearing a definite ratio to each other, which ratio, however, may be changed at will from time to time by suitably adjustin the trough or trou hs T.

ince the rate of ow of reflux liquid 0 through the line J into the top of the column A bears afixed ratio to the rate of flow of vapors upwardly through the column A, and since at each lower or intermediate stage the total "reflux liquid is divided into streams bearin a fixed ratio to each other, both the rrate o removal of intermediate product and the rate of flow of returned reflux liquid bear of vthe vapors-upwardly through the column A, notwithstanding variations in the quantitiesof vapors rising upwardly through the column A per unit of t1me.

It will be noted that for eifecting the aforesaid division of the total reflux liquid this invention involves the use of means such as a fixedor constant ratio to the rate of flow flow box H which functions automatically,

i. e., without requiring adjustment, to maintaln the aforesaid ratio between said streams or between the rate of flow of refluxing liquid and the rate of flow of rising vapors, fixed or constant, as redetermined, irrespective of the variations 1n the flowof said vapors or the rate of input into the column. This ratio, however, may be changed if desired by suitably mani ulatmg head X of the flow box and for a efinite position of head X, as indi-- .cated by the pointer W, the ratio of the quantity of refluxing liquid to the quantity of rising vapors is maintained constant notwithstanding variations in the amounts of material to be'fractionated delivered into the column A per unit of time.

The material charged through the pipe C may be mineral oil, such as a mixture of coal tar products to be fractionated; or crude petroleum, such as a mid-continent or mixed base crude or a parafline base crude; or the material may be a mixture of petroleum components or products.

While the flow boxes M, M, M, etc., are described as if located external to the column A, which generally is preferable, it will be understood that the descending refluxing liquid may be divided into the proportloned streams within the column A itself.

What I claim is:

1. Apparatus for fractionally distilling a composite liquid comprising a fractionatmg column, means for introducing the material to be fractionated into saidcolumn, means for withdrawin vapor from the column, means for intro ucing into said column refluxing 1i uid, and means for withdrawin at a pointlaetween the top and bottom of said column at a rate substantially proportional to the rate of flow of vapors upwardly through said column a predetermined percentage of the total descending refluxing liquid, said percentage withdrawn being automatically maintained constant, as predetermined, irrespective of variations in the rate of flow of vapors upwardly through said 001- umn. 2. Apparatus for fractionally distilling a composite liquid comprising a fractionatin column, means for introducing the materia to be fractionated into sald column, means for introducinginto said column refluxing liquid, means or withdrawing vapor froin the column, means'fo'r dividing at a point between the to and bottom of said column the total descen ing refluxing liquid into streams whose magnitudes bear a substantially fixed ratio to each other, means for withdrawing "one of said streams from said column, means for directing'the other of said streams to operate as refluxing liquid in its further descent in fractionating relation to rising vapors, and

means for automatically maintainlng said fixed ratio", as predetermined, notwithstanding variations in the amounts of material to I be fractionated introduced into said column.

'ly maintaining the ratio of the refluxingliquid removed to the total descending refluxing liquid constant, as predetermined, irrespective of variations in the rate of flow of vapors upwardly in'said column. 4. Apparatus for fractionally distilling a composite liquid comprising a fractionatmg column, means for introducing the material to be fractionated into said column, means for Withdrawing vapors of the lowest boiling point constituents, means for condensing said vapors, means for returnin a substantially fixed percentage of the con ensate into said column as refluxing liquid, means intermediate the top and bottom of said column for removin a substantially fixed percentage of the total descending ,refluxing liquid, and means for automatically maintainin a substantially fixed ratio of refluxing l quid to the vapors in the column, as predetermined,

irrespective of variations in the amounts of material introduced into said column.

5. Apparatus for fractionally distilling a composite liquid comprising a fractionatlng column, means for introducing the material to be fractionated into said column, means for withdrawing vapor from the column, means for introduci into said column refluxing liquid, means or maintaining at any stage between the topand bottom of said column substantially constant the ratio of the quantity of the rising vapor to'the quantity of 1 descending refluxing liquid, and means for pensate for variations in the flow of said withdrawing a substantially fixed percentage of said liquid, the ercentage being maintained fixed, as pre etermined, without involving the necessity of adjustments to comliquid. a

6. Apparatus for fractional-11y distilling a composite liquid comprising a fractionating 7 column, means for introducing. the material t o be fractionated into said column, means for withdrawing vapor from the column, means for removing a portion of reflux liquid passing down through the column which is ,a substantially fixed proportion of vthe total reflux liquid irrespective of variations in the rated flow of the total reflux liquid, and ad justable means for automatically maintainmg the proportion between the reflux liquid removed and the total reflux liquid fixed, as predetermined, irrespective of variations in the rate of flow of the ,total reflux liquid.

-7. Apparatus for fractionally, distilling a composite liquid comprising a fractionating column, means for introducing the material to be fractionated into said colummmeans for Withdrawing va or from the column, means for condensing t e vapor withdrawn, means for dividing the condensate into streams which bear a substantially fixed proportion to each other, means for returning one of said streams into the column as reflux-liquid, means for removing at a point intermediate the top and bottom of the column a portion of the reflux liquid which is a substantially fixed proportion of'the total reflux liquid irrespective of the rate of flow of vapors in said column, and means for automatically maintaining the proportion of the reflux 1i uid removed to the total reflux liquid fixed, as predetermined, irrespective of the rate of flow of vapors in said column.

8. Apparatus for fractionally distilling a composite liquid comprising a fractionatlng column, meansfor introducing the material to be fractionated into said column, means for withdrawing vapor from the colunm, means for condensing the vapor withdrawn, means for dividing thecondensate into streams which bear a substantially fixed pro ortion to each other, means for automatica ly maintaining said proportion, as predetermined, irrespective of variations in the rate of flow of said condensate, means for returning one of said streams as refluxing liquid to the column, means for dividin the total descending refluxing liquid at a re etermined point into streams bearing a xed proportion to each other, and means for returning one of said streams to operate as refluxing liquid in its further descent in fractionating relation to rising vapors.

' 9. Apparatus for fractionally distilling a composite liquid comprising a fractionatm column, means for introducing the materia to be fractionated into' said column, means for withdrawin vapor from the column, means for dividlngrefluxing liquid passing down through the'column at a pointintermediate the top and bottom on1 the columninto streams which bear a substantially fixed ratio to each other, means for automatically maintaining said ratio, as predetermined, irrespective of variations in the rate of flow of. said refluxing liquid and means for removing one of said streams from the column. 10, Fractionating a paratus comprisin a fractionating column aving a vapor outfit, a condenser connected to said vapor outlet and a divided flow device connected tosaid condenser, said divided flow device including a compartment arranged to receive the condensate from. the condenser, a partition positioned in front of said compartment and arranged to divide the condensate into streams bearing a fixed proportion to each other, means connecting said divided flow device with said fractionating column and a one or more similar divided flow devices connected to said fractionating column intermediate the top and bottom thereof, said similar divided flow devices being arranged to divide the total descending refluxing liquid into streams bearing any fixed proportion to each other irrespective of variations in the flow of vapor in said column.

11. Fractionating apparatus comprising a fractionating column, a divided flow device connected thereto to receive refluxing liquid therefrom, said divided flow'device comprising a compartment for receiving the refluxing liquid and a partition positioned in said compartment and arranged to divide the liquid into streams bearing a fixed proportion to each other and means for conducting one of said streams from the divided flow device to said fractionating column.

12. Apparatus for fractionallv distilling a composite liquid comprising a fractionating column, means for introducing the material to be fractionated into said column, vmeans for withdrawing vapor from the column, means for condensing the vapor withdrawn, means for dividing the condensate into streams which bear a substantially fixed proportion to each other, means for automatically maintaining said proportion, as predetermined, irrespective of variations in the rate ofrflow of said condensate, means for returning one of said streams as refluxing liquid to the column, means for dividing the total descending refluxing liquid at a predetermined point into streams bearing a fixed proportion, as predetermined, to each other, means for automatically maintaining said proportion irrespective of variations in the rate of flow of the reflux liquid, and means for returning one of said streams to operate as refluxing liquid in its-further descent in fractionating relation to rising vapors.

13. Fractionating apparatus comprising a fractionating column, a divided flow device connected thereto intermediate thetop and bottom thereof arranged to receive refluxing liquid therefrom, said divided flow device comprising a compartment for receiving the refluxing liquid and a partition positioned in said compartment and arranged to divide the liquid into streams bearinga fixed proportion for withdrawin vapor from the column, means for dividing refluxing liquid passing down through the column at a point intermediate the top and bottom of the column into streams which bear a substantially fixed ratio to each other, means for automatically maintaining said ratio, as predetermined, irrespective of variations in the rate of flow of said refluxing liquid, means for changing said ratio and means for removing one of said streams from the column.

In testimony whereof, I have hereunto affixed my signature.

RICHARD B. CHILLAS, JR.

to each other, means for changing the proportion and means for conducting one of said streams from the divided flow device to said fractionating column.

14. Apparatus for fractionall distilling a composite liquid comprising a ractionating column, means for introducing the material to be fract onated into sald column, means 

